Resilient planar framework for supporting multiple groundworking tools

ABSTRACT

A normally rigid planar framework for mounting a large number of ground working tools is made resilient to accommodate the torsional forces exerted on the rigid structural members of the framework as it passes over uneven ground and the tools are subjected to varying forces as they move through the ground. Resilience of the framework is achieved by having the structural members which are normally rigidly fastened together, fastened together instead by resilient fastening which permits torsional flexing between the rigid members so fastened. Additionally, rigid structural members of the framework which normally are pivotally connected to permit movement only around the pin axis of the pivotal connection, are resiliently pivotally connected so that slight rotation of the structural members can occur around the other two axes which intersect the pin axis of the respective pivotal connections at mutual right angles.

This application is a division of our earlier application Ser. No.155,516 filed Feb. 12, 1988, now issued as U.S. Pat. No. 4,840,233.

The present invention relates to agricultural implements, and moreparticularly to a resilient planar framework for supporting amultiplicity of ground working tools, preferrably at variable heightsrelative to ground level, for purposes of, for example, tilling,cultivating, fertilizing, or seeding the soil.

In an earlier U.S. patent of Terrance Friggstad, U.S. Pat, No. 4,676,321of June 30, 1987, the invention there disclosed is a framework for suchground working tools, the framework being exceptionally flexible andadaptable to rough ground contours, but somewhat expensive tomanufacture because its design generally required the use of a largenumber of ball and socket joints between structural members, to reducethe stress placed on the members when they moved relative to one anotherin passing over undulating ground. Furthermore, the exceptionalflexibility created problems in folding multi-sectional implements totransport position.

The framework of the present invention provides a simpler design inwhich fewer joints requiring the immense flexibility of ball and socketjoints are required to connect the structural members, and many of thejoints between structural members requiring only limited articulationaround three axes of rotation intersecting at mutual right angles can beof a much less expensive form than classic ball and socket joints. Itmay be noted at this point that a ball and socket joint connecting tworigid structural members permits relative movement of the members aroundthree axes of rotation intersecting at mutual right angles, although themovement around one or more of the axes may be restricted or limited. Auniversal joint connecting two rigid structural members permits relativemovement of the members around two axes of rotation intersecting atright angles, rotation of one of the members around the third axisintersecting the others at mutual right angles inexorably beingtransmitted to the other member through the universal joint, thuspermitting a driving shaft to transmit its torque through a universaljoint to a driven shaft. A pin joint connecting two rigid structuralmembers generally permits relative movement of the members around nomore than one axis, that being the axis through the center of the pin.

In the aforementioned earlier U.S. Pat. No. 4,676,321 at least twoflexibly linked parallel rigid bars for supporting ground working toolsare linked by pairs of parallel rigid links, which maintain the bars inparallel relationship. The parallel rigid bars are supported on wheelsmounted below and ahead of the rigid bars; power means are used todisplace the parallel rigid links relative to one another and therebyrotate the rigid bars around the axles of their respective supportingwheels, thus raising or lowering the rigid bars relative to the groundand so varying the height or depth of penetration into the ground ofground working tools fastened to the rigid bars. A preferred form of theaforementioned invention utilizes three ranks o parallel rigid bars,With each rank being flexibly linked to one other rank by pairs ofparallel links, thus providing complete flexibility between the ranks oftools of the implement in the longitudinal direction, i.e. from front toback of the implement. Flexibility of the implement in the transversedirection for the wide embodiments preferred for efficient agriculturaloperations is achieved by having the ranks of rigid bar divided intosections which are flexibly connected so that wing sections on the sideof a center section can rise and fall when passing over undulatingground independently of the movement of the center section. As isconventional in the agricultural implement art, provision also is madeto lift the wing sections hinged to the center section to a transportposition using suitable power means, thus permitting passage of the wideimplement through farm gates and along roadways.

It has been found that flexibility between the longitudinally spacedranks of ground working tools is not critical when the distance betweenthe front and rear ranks of the ground working tools is small relativeto the length of the ranks of the ground working tools, i.e. relative tothe width of the implement. It is thus unnecessary to have each rank ofground working tools and the rigid bars on which they are carried,supported on individual respective sets of wheels around whose axles therigid bars must be rotated to vary the operating depth or height of theground working tools. Thus the prior art need for the multiple pairs ofparallel rigid links and for the numerous ball and socket jointsrequired to connect them to the rigid bars can be eliminated by adifferent arrangement for varying the elevation above ground level ofrigid bars on which ground working tools can be mounted. These rigidbars are hereinafter referred to as tool mount bars.

The present invention thus consists of a height adjusting mechanism fora framework that supports a multiplicity of ground working tools of anagricultural implement whereby the tools can be variably positioned forvariable ground penetration, comprising:

(a) a set of at least four wheels mounted on two horizontally andlongitudinally disposed wheel frames, each wheel frame being supportedby at least two of said wheels, disposed proximate the respective endsof said frames,

(b) two rigid, longitudinally disposed, rock shafts, each pivotallyattached to, at two points proximate the two ends of, a respective oneof said wheel frames, said rock shafts being adapted to pivot relativeto their respective wheel frames on longitudinal axes passing throughthe pivotal attachments on their respective wheel frames, at variableelevations above their respective wheel frames,

(c) two longitudinally spaced, transversely disposed, rigid, horizontal,tool mount bars, each pivotally attached, adjacent its two ends, to thetwo said rock shafts, said tool mount bars being disposed above saidrock shafts and adapted to support two ranks of ground working tools,

(d) at least two longitudinally disposed, rigid, frame bars,transversely spaced along said tool mount bars and fastened thereto tomaintain the latter in spaced parallel relationship, and

(e) power means to pivot said rock shafts in opposite directions,simultaneously and through equal angles, around their respective pivotalaxes.

In a preferred form of the invention, a third tool mount bar is disposedtransversely behind the first two tool mount bars and is fastened to thetwo frame bars, thereby providing support for a third rank of groundworking tools.

A more preferred form of the invention provides a multisection frameworkfor supporting a multiplicity of ground working tools of an agriculturalimplement comprising, as a center section, a framework with heightadjusting mechanism as defined above and further comprising on each sideof said center section framework, at least one wing section of frameworkfor supporting a multiplicity of ground working tools, each said wingsection comprising:

(a) a set of at least two longitudinally spaced wheels mounted on ahorizontally and longitudinally disposed wing section wheel frame,

(b) a rigid, horizontally disposed, wing section rock shaft, pivotallyattached to said wing section wheel frame at points proximate saidwheels and adapted to pivot relative to said wheel frame on a horizontallongitudinal axis passing through said points of pivotal attachment tosaid wheel frame, at variable elevations above said wheel frame,

(c) longitudinally spaced, transversely disposed, rigid, horizontal,wing section tool mount bars, each one being aligned with acorresponding tool mount bar of said center section, pivotally attachedat its end nearer the center section to the adjacent end of thecorresponding tool mount bar of the adjacent section, and adapted topivot on a horizontal axis through the respective pivotal attachmentsbetween the corresponding tool mount bars, the distal ends of the firstand second of said tool mount bars of said wing section being pivotallyattached to and disposed above said wing section rock shaft,

(d) a longitudinally disposed, rigid, wing section frame bar, fastenedto each said wing section tool mount bar to maintain the latter inspaced parallel relationship, and

(e) means, connected to said power means, to pivot said wing sectionrock shaft through equal angles simultaneously with, and in the samedirection as, the pivoting of the adjacent rock shaft of said centersection.

The invention further consists in a resilient planar frameworksupporting a multiplicity of groundworking tools, said frameworkcomprising rigid structural members having resilient fastenings betweensaid rigid members which are fastened together, and having resilientpivotal attachments between said rigid members which are pivotallyattached, said resilient fastenings being adapted to permit torsionalflexing between the rigid members so fastened and said resilient pivotalattachments being adapted to permit relative movement between pivotallyattached rigid members around the two axes at mutual right angles to theaxis of their pivotal attachment.

To simplify an understanding of the present invention, it should beappreciated that practically all wheeled vehicles, including farmimplements, have and maintain some fixed transverse spacing betweentheir wheels. For example, railway car wheels must remain uniformlyspaced apart transversely of the railway car in order for the car toremain on the rails. Similarly automobiles, trucks, farm tractors, andmost other multi-wheeled vehicles including agricultural implementshaving transversely spaced wheels, maintain some fixed transversespacing between those wheels. The present invention foregoes the conceptof having or maintaining a fixed transverse spacing between wheels, andthereby makes provision for an effective arrangement for varying theelevation, relative to ground level, of ground working tools beingsupported by those wheels.

The invention will be more readily understood from the ensuingdescription thereof with reference to the accompanying drawings whereinthe same numbers are used to identify identical parts throughout thedrawings and in which:

FIG. 1 is a diagrammatic isometric projection, omitting numerousextraneous parts, of essential structural members of a simple embodimentof the invention.

FIG. 2 is another diagrammatic isometric projection, again omittingnumerous extraneous parts, showing an arrangement of some of theprincipal parts of a more extensive embodiment of the invention, morespecifically a five section implement having a center section and twowing sections on each side thereof.

FIG. 3 is an exploded partial view of some of the parts used to assemblean embodiment of a resilient fastening between a tool mount bar and aframe bar initially preferred in the invention.

FIG. 4 is a front elevation of a preferred embodiment of the powermeans, utilizing a single hydraulic cylinder to achieve simultaneous andequal variation in the elevation of ground working tools of a center andinner wing section of framework.

FIG. 5 is an extension of FIG. 4 showing the extension of the powermeans of FIG. 4 past an inner wing section to an outer wing section.

FIG. 6 is a cross sectional side elevation, viewed from the center lineof a center section, of parts of a preferred center section embodiment.

FIG. 7 is a plan view of the parts shown in FIG. 6.

FIG. 8 is an isometric projection illustrating the spatial arrangementof some critical parts of one symmetrical half of a center section, aninner wing section, and part of an outer wing section in one embodimentof the invention, in particular two rock shafts and their connections

FIG. 9 is an end view of the flanged end of a tool mount bar showingresilient pivotal connections between the tool mount bar and a rockshaft and between the tool mount bar of one section and the tool mountbar of an adjacent section.

FIG. 10 is an illustration in an exploded view, of one embodiment of apair of clevis and tongue mounted spherical bushings forming a resilientfastening between two rigid structural members.

FIG. 11 is a cross-section through one of said pair of sphericalbushings.

In FIG. 1, structural members, which are of conventional structuralsteel construction, are shown diagrammatically and out of proportion forsimplicity of illustration. The figure shows a simple planar frameworkin accordance with one embodiment of the invention, the framework beingsupported on the ground by a pair of three wheeled "tricycle" frames, 1,all three wheels, 2, of each frame being shown. The length of the frames1 is not critical, it being chosen to place the wheels at the mostconvenient positions longitudinally with reference to the tool mountbars, thereby carrying the load of the framework most effectively. Thereare two pairs of pivot points, C1 and C2, one pair on each wheel frame,each conveniently in lugs or small flanges, each rigidly secured to itsrespective frame. Theoretical axes, C pass through these pairs of pivotpoints. Pivotally attached to the respective forwardmost pivot points C1and C2 are connecting members or rigid flanges 3 and 4 respectively, theflanges being rigidly secured to, and adjacent, the forward ends ofrigid rock shafts 5 and 6 respectively. Rearwardly along rock shafts 5and 6 from flanges 3 and 4 respectively are rigid flanges 7 and 8, eachfastened rigidly to its respective rock shaft and attached pivotally tothe respective rearwardmost pivot points C1 and C2 respectively. Flanges3, 7, 4, and 8 project upwardly and outwardly from their respectivepivot points C1 and C2, outwardly in this instance meaning substantiallyat right angles away from the longitudinal center line of the framework.Additionally, rigid flange levers 9 and 10, conveniently being rigidextensions of flanges 7 and 8 respectively, project upwardly from rockshafts 5 and 6 respectively. The top flange lever 9 is pivotallyattached at pivot point 11 to one end of a rigid bar mechanism 12containing an hydraulic ram 13. The distal end of bar mechanism 12 isfastened to a fixed point on a convenient rigid framework member, inthis embodiment rigid frame bar 14. Similarly the top of flange lever 10is pivotally attached at pivot point 15 to one end of another rigid barmechanism 16 containing anothe hydraulic ram 17. The distal end of barmechanism 16 also is fastened to a fixed point on a convenient rigidframework member, in this embodiment rigid frame bar 18. The two rigidbar mechanisms are principal parts of the power means to pivot the rockshafts 5 and 6 in opposite directions simultaneously and through equalangles around their respective axes C passing through the pairs of pivotpoints C1 and C2 respectively.

Operation of the power means will be explained more fully subsequentlyherein.

Two or more longitudinally spaced, horizontal, rigid, tool mount barsare transversely disposed across frame bars 14 and 18, and fastened toeach of them. The two essential tool mount bars are designated as 19 and20, and an optional third one is indicated by the dotted member 21,fastened to the extensions of frame bars 14 and 18, also indicated bydotted lines. At each end of each of horizontal tool mount bars 19 and20 there are short, rigidly mounted, vertically disposed, rigid flanges22 extending above and below the level of the tool mount bars. Thelength of these flanges is exaggerated in figures of the drawings forclarity of illustration. Tool mount bar 21 also has vertical flanges 22which need extend only above the tool mount bar 21. Near the bottom endof flanges 22 on tool mount bars 19 and 20 there are pivotingconnections or attachments A1 to lugs or flanges on rock shaft 5 andpivoting connections or attachments A2 to lugs or flanges on rock shaft6. Two respective theoretical axes, A, pass through these pivotingconnections A1 and A2 respectively. Near the top end of flanges 22 ontool mount bars 19, 20 and 21, there are pivoting connections B1 and B2for optional attachment of tool mount bars of adjacent wing sections offrame work. Two respective theoretical axes, B, pass through thesepivoting connections B1 and B2 respectively. Optional wing sections offramework on each side thus can pivot about the B axes respectively,providing ample lateral flexibility for wide implements of multiplesections, as illustrated in FIG. 2.

Previously mentioned rigid horizontal frame bars 14 and 18 extendsubstantially longitudinally between the tool mount bars, and arefastened thereto to maintain the tool mount bars in spaced parallelrelationship and to transmit the pull, applied by drawbar 23, to all thetool mount bars. The frame bars are pivotally attached to the drawbar,as is conventional in the art. Various forms and designs of drawbar maybe used to pull the framework, from the simple A-frame designillustrated in FIG. 1 to any of numerous, more complicated designs moresuitable for multi-section frameworks illustrated in FIG. 2.

The rigid bar mechanisms 12 and 16 were referred to earlier herein asprincipal parts of the power means to pivot the rock shafts 5 and 6 inopposite directions (namely clockwise and counter-clockwise)simultaneously and through equal angles around their respective axes Cpassing through pivot points C1 and C2 respectively. Simultaneous andequal displacement of the hydraulic cylinders 13 and 17 is obtained byphasing the cylinders, that is to say arranging the hydraulic supplylines to and from a pair of identically sized cylinders so that, toextend the cylinders, hydraulic fluid pressure is applied to onecylinder only and the pressure is transmitted through that cylinder tothe second cylinder connected hydraulically in series therewith; tocontract the cylinders, hydraulic pressure is applied only to the secondcylinder and the pressure transmitted through the second cylinder backto the first through the hydraulic series connection. Other embodimentsof power means, described in more detail later herein, can be used inlieu of the dual phased cylinder arrangement just described, to achievesimultaneous and equal displacement of the rock shafts. It may bementioned here briefly that, for example, a single hydraulic cylinder orhydraulic ram can be mounted to extend and contract between a pivotinglever and a pivoting link, the lever and the link being pivoted on thesame rigid tool mount bar, with a rigid evener link pivotally connectingthe pivoting lever and pivoting link, to ensure simultaneous equaldisplacement of each end of the hydraulic cylinder against rigid barslinking the hydraulic cylinder to respective rock shafts.

From the foregoing description it can be seen that power means is usedto displace, outwardly (i.e. away from the longitudinal center line ofthe framework), simultaneously, and in equal amounts, two rigid barspivotally connected at their distal ends to the two flange levers 9 and10 respectively. Displacement of the said bars displaces the flangelevers 9 and 10 and forces them, and the rock shafts 5 and 6 to whichthey are respectively rigidly fastened, to rotate in respective arcsaround theoretical axes A running through pivoting connections A and A2respectively. As the rock shafts rotate on axes A, they force theflanges 3 and 7 on rock shaft 5, and flanges 4 and 8 on rock shaft 6,also to move in arcs around axes A. The axes A remain a fixed distanceapart, the distance being determined by the length of the rigid toolmount bars 19 and 20 on the ends of which are the rigidly mountedvertical flanges, through the lower parts of which the respective A axespass. As the rock shafts and flanges 3, 7, 4 and 8 move around axes A,the vertical distance between the tool mount bars, 19 and 20, and thewheel frames, 1, changes, thus varying the position, relative to theground, of any tools mounted on the tool mount bars. Because the A axesremain a fixed distance apart, as previously noted, not only does thevertical distance between the tool mount bars and the wheel frames 1change, but also the transverse distance between the wheel frames 1changes. Thus the framework of the present invention does not have afixed transverse spacing between its wheels, but permits this spacing tochange as the elevation of the ground working tools relative to theground is changed. There is no problem created by a varying transversespacing of the wheels of the framework, as there is no need for it toremain constant as there is, for example, with vehicles running onrails.

Better understanding of the operation of the rock shafts may be gainedfrom FIG. 8, showing two of the three identical rock shafts 5 which havethe same configuration as the third of the three rock shafts on the lefthalf of the five section framework illustrated in FIG. 2 Rock shafts onthe other half of the framework of FIG. 2 would be identical butconnected to the corresponding parts to pivot in the direction oppositeto the pivoting of the rock shafts referred to on the left half of FIG.2. Thus FIG. 8 shows some parts of the center section, the inner leftwing section, and the outer left wing section, with wheel frame 1 of thecenter section and wheel frame 33 of the inner wing section, mounted onwheels 2 supporting flanges 3 and 7, via lugs on the wheel frames, atpivot points C1. Rock shaft 5 is rigidly fastened to flanges 3 and 7.Flange lever 9, also rigidly fastened to the rock shaft, is connected atpivot point 11 to one end of rigid bar mechanism 12; in the case of rockshafts of wing sections, the flange levers corresponding to 9, i.e. 32and 37 in FIGS. 4 and 5, are pivotally connected to extension bars, 31and 36, as more fully explained later with reference to FIGS. 4 and 5.Tool mount bars 19 and 20 are held in parallel spaced relation by framebar 18 Rigid flanges 22 on the ends of the tool mount bars extend aboveand below these bars. Flanges 3 and 7 on rock shaft 5 also are pivotallyattached at pivot points A1 near the bottoms of flanges 22. Near the topends of flanges 22 are pivot points B1 at which tool mount bars of theadjacent wing section of framework are pivotally attached, 34 beingtypical of such tool mount bars shown in both FIG. 8 and FIG. 4.Extension bar 31, pivotally attached to rigid bar mechanism 12 at pivotpoint 11, transmits the displacement of rigid bar 12 to rotate the rockshaft of the adjacent wing section, in both FIGS. 8 and 4. Power means,as previously described, displaces the rigid bars and extension bars, oneach side of the centerline of the framework, by equal amounts androtates each of the rock shafts in equal arcs around the pivot points A1and the A axes through their respective flanges 22.

To facilitate turning of the framework of this invention it is desirablethat the front wheels on the wheel frames be castor mounted. Aparticularly effective castor mounting is the double castor mountingshown diagrammatically in FIG. 1. The horizontal axle of the wheel isheld at its ends by a pair of crab claw shaped arms which extend out andback from the axle and are each pivotally attached, at their distalends, to vertical pivots on the ends of a transverse bar on the front ofthe wheel frame. The attachments of the axle ends to the front of thearms also are on vertical pivots. The double castoring provided by thetwo pairs of vertical pivots between the horizontal axle and the rigidwheel frame provides great flexibility in the turning of the wheel andpermits it to turn on a very short radius, thus facilitating the turningof the implement when it is pulled around a sharp curve. Another majoradvantage of the arrangement is its low profile, which enables it toavoid interference with drawbar members, which can move freely over thecastoring wheels. An alternative castoring wheel arrangement is shown inFIG. 6 and 7.

It is a most preferred feature of this invention that the tool mountbars be resiliently, not rigidly, fastened to the frame bars. Rigidfastening of the tool mount bars to the frame bars creates a rigid planeof these members Resilient fastening permits torsional flexing betweenthe rigid members so fastened, that is slight rotational movement of atleast one of the rigid members about an axis or axes parallel andproximate the theoretical plane passing through the members at theirpoint of attachment. Furthermore it is a most preferred feature of theinvention that some pivotal connections between some rigid structuralmembers, all of which connections are classifiable as pin joints, shouldalso provide some resiliency so that slight rotation can occur aroundthe other two axes which intersect the pin axis of the respectiveresilient pivotal connections at mutual right angles. Such resiliencymodifies the nature of the specified pivotal connections or pin jointsof the invention, providing them with characteristics of the moreflexible ball and socket joints. It is for this reason that a number ofthe rigid members can be defined as being resiliently pivotally attachedto other rigid members, and not defined simply as being pivotallyattached. However, the height adjusting mechanism of the invention doesnot depend on flexibility or resiliency of the planar framework forsuccessful operation, the mechanism being effectively operable on acompletely rigid framework. Nonetheless. resiliency in the framework ispreferred for durability. Some further details for providing resiliencyto the pivotal connections are mentioned subsequently herein.

Referring again to the resilient fastening of the frame bars to the toolmount bars, the framework of this invention could be overstressed andimpractical if the frame bars were rigidly fastened to the tool mountbars, as, for example, by welding, riveting, or rigidly bolting them.Considering for example a four wheeled center section, there are fourpoints of support on the wheel frames for all the framework above thewheel frames. When the wheels are on uneven ground, with no load on theframework, three of the wheels could be supporting the framework on theground and the fourth wheel held in the air by the plane of thesubstantially rigid framework. Under load of numerous ground workingtools working in the soil on such uneven ground, the plane of theframework inexorably tends to distort and weigh the fourth wheel downinto contact with the ground. Under such distortion, rigid fasteningsbetween frame bars and tool mount bars are prone to, and likely to,fracture, for example by shearing of bolts or rivets or welds,particularly in framework sections having three or more tool mount bars.To accommodate such distortion, the wheel mount bars and frame bars inthe present invention preferably are fastened together to provideresilience in the fastenings, thereby providing for flexing, for exampletorsional flexing, between the structural members. An example of aresilient fastening between a tool mount bar, for example 20, and aframe bar, for example 14, is a pair of loose clevis and tongueconnections, or a pair of clevis and tongue mounted spherical bushingsforming a pair of ball and socket joints. FIGS. 10 and 11 illustrate onesimple fastening using a pair of spherical bushings to fasten a toolmount bar, 20, to a frame bar, 14. A first pair of lugs, 61, rigidlyfastened to frame bar 14, form a first clevis and a second pair of lugs,62, also rigidly fastened to frame bar 14, form a second clevis. Thetool mount bar 20 has two tongues, 63 and 64, rigidly fastened thereto,protruding from opposite sides of the tool mount bar, each tongue havingone of a pair of spherical bushings, 65 and 66, mounted therein. Clevispins 67 and 68 are fitted through the respective clevis when therespective tongue with its spherical bushing has been fitted into itsclevis. From FIG. 11 it can readily be seen that the combination of lugs61 and 62 with clevis pins 67 and 68 will fasten the tongues 63 and 64,and tool bar 20, to frame bar 14 but still allow the tool bar to twist,i.e. accommodate torsional flexing, around the axis through the middleof the two clevis pins perpendicular to the plane of the cross-sectionshown in FIG. 11. Another example of a resilient fastening isillustrated in FIG. 3. A rigid bracket 24 rigidly fits around tool mountbar 20, and has flanges 25 on each side of the tool mount bar. Boltholes in the flanges of the bracket are aligned with bolt holes in framebar 14. Before bolting bracket 24 to frame bar 14 with a bolt and nutassembly 26 for each bracket hole, at least one large resilient washer,50, for example of from 5 to 10 or more cm diameter and 1 to 2 or morecm thickness, is placed around each bolt between the bracket flanges 25and the frame 14. These resilient washers can be made, for example, fromnatural rubber, synthetic rubber, resilient polyurethane plastic, orother durable, resilient material. When assembled, the bolt and nutassemblies are not tightened to compress the resilient washer to itsmaximum compressibility, but left loose enough that the washer cancompress further over various segments of its circumference to permitrotation of either the frame bar or the tool mount bar with respect tothe other around their axes in horizontal planes. As shown in FIG. 3,the bracket permits ample resiliency for torsional rotation of toolmount bar 20 around the axis of frame bar 14; demand for torsionalrotation of the frame bar around the axis of the tool mount bar isgenerally negligible in comparison, and is adequately provided by thebracket and resilient washers. In another embodiment, resiliency couldbe obtained at the fastening by using a substantially identical assemblybut, instead of resilient washers, with strong, partially compressed,coiled springs providing resiliency at each bolt. In still othervariations, belleville washers, or a stack of partially compressed splitlock washers could be substituted for the single resilient washerdescribed above.

It has been mentioned above that it is most preferred to have resiliencyin a number of the pivotal connections between rigid parts in theframework. These resilient pivotal connections include, for example asshown in FIG. 9, the connections between the rock shafts and tool mountbars, and between tool mount bars and adjacent tool mount bars.Resiliency in such pivotal connections or pin joints is readilyobtained, for example, by having the pivot pin hole, through one of thetwo parts being pivotally connected, of somewhat larger diameter thanthe pin, so that the part with the larger diameter hole is somewhatloose on the pin and is free to rotate on axes at right angles to theaxis of the pin. At the same time that the foregoing looseness isprovided, it is most preferred to make provision for maintaining thepivotal connection, in its normal, unstressed position, in a cohesivefirm but resilient condition. This is readily done by providingresilient washers, 50, for example of the same materials used in thewashers described above for the resilient fastenings described above,around the pivot pin on either side of the part with the larger diameterhole, and filling with partially compressed resilient washer, the spacealong the pin between the parts being resiliently pivotally connected.Again, as for the resilient fastening described above, the resilientwashers could be replaced by strong, partially compressed, coiledsprings, or by belleville washers or stacks of partially compressedsplit lock washers. With pivotal connections thus rendered resilient,these pin joints are converted, to an appreciable degree, into ball andsocket joints, in that besides being able to move relative to oneanother around the axis of their pivot pin, rigid parts joined by theresilient pivotal connections are able to move relative to one anotheraround the two axes at mutual right angles to the axis of the pivot pin;the restricted degree of extra movement thus permitted between rigidparts is usually sufficient to eliminate or reduce greatly the stressthat would otherwise be put on one rigid part by abnormal movement ofanother rigid part pivotally connected thereto.

In FIG. 2 there is illustrated, by a diagrammatic representation, amultisection framework for supporting a multiplicity of ground workingtools in accordance with a further embodiment of the invention, having acenter section and two wing sections on each side thereof. A1l sixwheels of the center section are shown, but the "tricycle" wheel framesare not shown. However, the theoretical C axes, passing through thepairs of pivot points C1 and C2 respectively of FIG. 1 are shown, asdotted lines. The rock shafts 5 and 6 are not shown; however they wouldmost conveniently be located between the respective C and A axes, beinglongitudinally disposed therebetween. The "A" axes are shown as dot-dashlines. The pivotal attachment of rigid parts which are located along theA axes most preferably all are resilient pivotal connections, forexample as described earlier herein with reference to FIG. 9. The rigidflanges 3, 4, 7, and 8, pivotally connecting the rock shafts to thewheel frames, are shown to illustrate the relative positions of theseparts. A1igned with the tool mount bars 19, 20 and 21 respectively ofthe center section are the tool mount bars of the wing sections, thepreferably resilient pivotal connections between the laterally adjacentbars being along the B axes (the short dash lines) between the variousadjacent sections respectively. Being aligned along the B axes, thepivotal connections of the tool mount bars between the various sectionspermit ample flexing between the relatively rigid planes of therespective individual sections, and further permit folding of the wingsections towards the center section when it is desired to reduce thewidth of the implement drastically for easy transportation, as isconventional in the agricultural implement art. Besides the pivotalconnections between the tool mount bars along the B axes betweenadjacent sections, the only other connections between the sections arethe drawbar means and the means connected to the power means to pivotthe wing section rock shafts, simultaneously and through equal anglesaround their respective pivotal axes. Drawbar means, conventional in theart, make provision for flexing at pivotal connections between laterallyadjacent sections of multisection agricultural implements. Similarly,the power means to pivot the rock shafts extends transversely from thepoints of attachment to the rock shafts at points proximate the B axesof the center section, across the inner wing sections where it attachespivotally to the rock shafts of these sections at points proximate theirrespective B axes, and further across the outer wing sections to therock shafts where it again attaches pivotally at points proximate therespective B axes. These extensions of the power means from the centersection to the wing section most conveniently are in the form of simplerigid extension bars 31 (FIG. 4) which transmit the simultaneous andequal displacement of the rigid bar mechanisms 12 and 16 (FIG. 1) of thecenter section to the rock shafts of the respective adjoining wingsections. By connecting the extension bars to one another and to therigid bar mechanisms 12 and 16 at points proximate the respective Baxes, the whole rigid bar and extension bar arrangement is capable offlexing and folding along the B axes between sections when the frameworkis passing over uneven, undulating ground or being folded fortransportation.

It will noted that the wing section wheel frames, not shown in FIG. 2,are represented as having only two wheels each; thus the wheel frames ofthe wing section are "bicycle" wheel frames, although they could equallywell be "tricycle" wheel frames. "Tricycle" wheel frames are preferredfor the center section as they provide more wheels to carry the weightof the wing sections when the latter are folded into transport position,as is commonly done with wide agricultural implements. "Bicycle" wheelframes can provide adequate support for wing sections, but "tricycle"wheel frames, of lighter construction than those of the center section,can be used for the lighter loads carried by the wing section wheels,and may be preferred for their greater inherent vertical stability.

There has been mentioned earlier herein an optional embodiment of powermeans suitable to achieve simultaneous and equal displacement of therock shafts, whereby the height of the tool mount bars, and all groundworking tools mounted thereon, is uniformly varied. This embodiment isnow to be described with reference to FIG. 4. This figure is a frontelevation of two rigid bar mechanisms which both achieve their equaldisplacement power from the same single hydraulic ram or hydrauliccylinder. The two rigid bar mechanisms 12 and 16 are both pivotallyattached indirectly to a single transverse frame member, preferably thesecond tool mount bar 20. The rigid bar mechanisms also are pivotallyattached at opposite ends of the single hydraulic cylinder 27. Theindirect attachment of rigid bar mechanism 12 to tool mount bar 20 isachieved through rigid pivoting lever 28, which is pivotally attached,proximate its center, to one face, for example the front, of tool mountbar 20, and also pivotally attached at its first end to the end of thehydraulic cylinder 27 to which rigid bar mechanism 12 is pivotallyattached, on the same pivot. Indirect attachment of rigid bar mechanism16 to tool mount bar 20 is achieved through rigid pivoting link, 29,which is pivotally attached, near one of its ends, to the same face,i.e. the front, of tool mount bar 20 at an appropriate distance from thepivotal attachment of pivoting lever 28. The distal end of pivoting link29 is pivotally attached to the end of hydraulic cylinder 27 to whichrigid bar mechanism 16 is pivotally attached, on the same pivot. Thedistal end of pivoting lever 28 is pivotally attached to one end of arigid evener link, 30, the distal end of which is pivotally fastened tothe pivoting link 29, optionally on the same pivot as the attachment ofpivoting link 29 to hydraulic cylinder 27 and rigid bar mechanism 16.A1ternatively, to avoid crowding of members at pivotal attachments, thedistal end of evener link 30 can be pivotally attached to pivoting link29 at a pivot point at a location between the pivot points near the endsof pivoting link 29, as shown by the dotted line position of evener link30. The pivotal attachments of this link are arranged to allowequivalent rotation of lever 28 and link 29 and thus equal displacementof the ends of cylinder 27 as it extends or contracts. The end of rigidbar mechanism 12 remote from hydraulic cylinder 27 is pivotally attachedto rigid flange lever 9 at pivot point 11 (FIG. 1), the flange lever 9being rigidly fastened to rock shaft 5, not shown in FIG. 4. A1sorigidly attached to rock shaft 5 is rigid flange 7. Near its lower endthe flange 7 is pivotally attached at pivot points C1 to wheel frame 1.It can readily be seen from FIG. 4 that extension and contraction ofhydraulic cylinder 27 displaces rigid bar mechanism 12 and rotatesflange lever 9 and its rigidly fastened rock shaft around axis A whichpasses through pivoting connection A1 on the rock shaft and the bottomof flange 22 on tool mount bar 20. At the same time the rock shaft andrigidly fastened flange 7 will rotate around pivot point C1 on top ofwheel frame 1, varying the relative elevation of tool mount bar 20 withreference to wheel frame 1 which, through wheels 2, rests on the ground.When rigid bar mechanism 12 of this embodiment is displaced, rigid barmechanism 16 is likewise displaced, and by the operation of the evenerlink 30, is displaced an equal amount, causing equivalent rotation ofrock shaft 6 at pivoting connection A2 and through flange 8 around pivotpoint C2 and the other wheel frame 1.

At pivot point 15, where rigid bar mechanism 16 pivots on flange lever10, a rigid extension bar 31 also is pivotally attached and serves totransmit the displacement of rigid bar mechanism 16 to the rigid flangelever 32 on the rock shaft of an adjacent wing section having its wheelframe 33. In this manner the tool mount bar 34 of the wing section hasits relative elevation, with reference to its wheel frame, variedsimultaneously and in the same amount as that of the center section toolmount bars. The wing section tool mount bar 34 is pivotally attached toflange 22 on tool mount bar 20 at pivoting connection B2.

When it is desired to raise the wing sections into transport positiontheir tool mount bars will pivot on the B axes and the tool mount barswill be in a raised position so that attached ground working tools willbe clear of the ground. With the tool mount bars thus raised, the pivotconnection 15 between rigid bar mechanism 16 and extension bar 31 willbe in close proximity to, if not exactly aligned with, axis B, so thatrotation of the wing section about axis B will cause only slight, ifany, variation in displacement of rigid extension bar 31 relative to therest of the wing section, thus moving the wheel frame mechanismslightly, at most, and well within the bounds of its operating range ofmovement. Thus the extension bar 31 can fold conveniently with the toolmount bars.

In the same manner that the end of the wing section tool mount bar 34,adjacent the center section, pivots at pivoting connection B2 on flange22 of tool mount bar 20, FIG. 4, an end of tool mount bar 35 (FIG. 5)pivots at a pivotal connection B3 on a flange 22 at the outer end oftool mount bar 34. Tool mount bar 35 forms part of an outer wing sectionwhich has its respective rock shaft, wheel frame, and wheels, and israised or lowered simultaneously with the center and adjacent wingsections by displacement of another rigid extension bar 36 pivotallyattached at one end to extension bar 31 at the pivoting connection ofthe latter to flange lever 32 on the rock shaft of the first or innerwing section. The distal end of extension bar 36 is pivotally connectedto flange lever 37 on the rock shaft of the outer wing section havingits wheel frame 38. The tool mount bar 35 of the outer wing section hasits relative elevation, with reference to its wheel frame 38, variedsimultaneously and in the same amount as that of the center section andinner wing section tool mount bars, by the simultaneous displacement ofthe

Numerous modifications can be made in the various elements of theinvention besides those already indicated in detail above. For example,the wheel frames, which are carried by front and rear wheels of eachsection, are not necessarily unitary nor rigid, nor do they necessarilyextend directly between their respective front and rear wheels. Thus arigid elongated front part of a wheel frame can have its forward endmounted on a castoring front wheel and its rearward end pivotally andslidably attached, on a horizontal transverse axis, to a tool mount bar,while a separate rigid rear part of said wheel frame is mounted on therespective rear frame wheel or transversely spaced wheels and ispivotally attached, on a generally longitudinal axis, to its respectiverigid rock shaft which also is pivotally attached, on a generallyhorizontal axis, to the rigid front part of the wheel frame. The rockshaft, pivotally attached to each of the front and rear parts of thewheel frame, thus serves to distribute the load, applied to the rockshaft by the tool mount bars which are mounted thereon, to both thefront and rear parts of the wheel frame and hence to the front and rearwheels, even though the front and rear parts of the wheel frame areseparate, because these parts are directly pivotally connected by therock shaft, which is rigid. Furthermore, with an arrangement of separatefront and rear wheel frame parts as just described, it is not necessarythat a rock shaft be horizontally aligned, nor that it be straight. Forconvenience a rock shaft can be inclined so that the pivoting axisbetween said rock shaft and the tool mount bars mounted thereon isinclined to intersect the horizontal axis through the pivot pointsbetween tool mount bars of adjacent framework sections. By having suchintersection at a pivot point in folding drawbar means used to draw theframework over the ground, the folding of the drawbar means with thefolding of the wing sections for transportation purposes is facilitated;other advantages also accrue to the use of an inclined rock shaft. Withthe pivot axis between the rock shaft and tool mount bars thus inclined,the pivot axes between the rock shaft and the wheel frame or wheel frameparts also must be inclined so as to be parallel to said first mentionedinclined axis, thus permitting freedom of rotation of the rock shaftsimultaneously about all the points of pivotal attachment thereof.Rotation of the rock shaft causes lateral displacement of the rock shaftand wheel frame, as well as relative vertical movement between the two.Because the rearward end of the front part of the wheel frame in thisembodiment is slidably pivotally attached to a tool mount bar, lateraldisplacement of this end of said wheel frame part is readilyaccommodated.

An example of an embodiment of the features just described isillustrated in FIGS. 6 and 7 of the drawings. In these Figures a frontwheel 2 is castor mounted in and supports the forward end of theelongated front part 1F of a wheel frame. A pair of rear wheels 2R ismounted to provide support for the rear part 1R of said wheel frame. Therearward end of said front part of the wheel frame is pivotally andslidably attached, at horizontal, transverse, pivot axis 39, to theunderside of front tool mount bar 19. Frame bar 18 connects tool mountbars 19, 20, and 21. Rock shaft 5, beyond the wheel frame in the view ofFIG. 6. is supported at its forward end on the front part 1F of thewheel frame, to which it is pivotally connected by rock shaft flange 3at pivot point C1. This pivotal connection preferrably is a resilientpivotal connection as illustrated in FIG. 9 between rock shaft flange 7and tool mount bar flanges 22. Rock shaft 5 is supported at its rearwardend on the rear part IR of the wheel frame, to which it is pivotallyconnected by flange 7 at one or more pivot points on longitudinal pivotaxis C3. Rock shaft 5 supports tool mount bars 19 and 20 which arepivotally connected to the rock shaft by respective flanges 22 on thetool mount bars and corresponding flanges on the rock shaft. Throughthese pivotal connections in flanges 22 passes the A axis about whichthe rock shaft pivots relative to the tool mount bars. In thisembodiment the A axis is inclined to the horizontal and inclinedparallel thereto are the pivot axis C3 and the axis at pivot point C1;as previously mentioned, the inclined A axis preferably intersects thehorizontal B axis passing through the pivot points in the connectionsbetween the tool mount bars of an adjoining section (not shown in FIG.7).

A large agricultural implement with resilient planar frameworks forsupporting a multiplicity of ground working tools, as disclosed herein,is capable of flexing, to assume the contours of the ground over whichit is passing, in a vastly superior fashion to any framework which isrigidly planar. Hence the resilient planar framework disclosed herein isthe most preferred framework for use with the height adjusting mechanismdisclosed herein.

Numerous other modifications can be made in the various expedientsdescribed herein without departing from the scope of the invention whichis defined in the following claims.

What is claimed is:
 1. A resilient planar framework supporting amultiplicity of groundworking tools, said framework comprising at leastone planar section of connected, rigid, structural members with some ofsaid rigid structural members being rigidly fastened together, (b) atleast two of said said rigid structural members being fastened togetherby resilient fastenings, and (c) at least two of any of said rigidstructural members being pivotally attached together by resilientpivotal attachments, said resilient fastenings being adapted to permittorsional flexing between the rigid members so fastened and saidresilient pivotal attachments being adapted to permit relative movementbetween the pivotally attached rigid members around two axes at mutualright angles to the axis of their pivotal attachment.
 2. A resilientplanar framework as claimed in claim 1 in which the rigid structuralmembers fastened by resilient fastenings are parallel, spaced, toolmount bars fastened resiliently to frame bars which maintain the toolmount bars in spaced parallel relationships, said tool mount bars beingfastened resiliently to a respective frame bar by a respective rigidbracket which fits around three sides of the tool mount bar and holdsthe fourth side of the tool mount bar to a frame bar with bolt and nutassemblies on opposite sides of the tool mount bar, the assemblies eachincluding a resilient washer which is tightened by said bolt and nutassemblies to compress the washer at less than the maximumcompressibility of the washer, thereby fastening the tool mount barsecurely, yet resiliently, to the frame bar.
 3. A resilient planarframework as claimed in claim 1 and further comprising, the washer atless than the maximum compressibility of the washer, thereby fasteningthe tool mount bar securely, yet resiliently, to the frame bar beingresiliently pivotally attached at its side nearer the center section tothe adjacent side of the center section by resilient pivotalattachments, said pivotal attachments each having (a) pivot pin holes oflarger diameter than their respective pivot pins and (b) partiallycompressed resilient washers on said pivot pins to maintain the pivotalattachments, in their normal, unstressed position, in a cohesive, firm,but resilient condition.
 4. A resilient planar framework as claimed inclaim 1, in which said framework comprises:(a) two horizontally andlongitudinally disposed wheel frames, each wheel frame being supportedby at least two wheels disposed proximate the respective ends of saidframes, (b) two rigid, longitudinally disposed rock shafts, eachpivotally attached to, at two points proximate the two ends of, arespective one of said wheel frames, said rock shafts being adapted topivot relative to their respective wheel frames on longitudinal axespassing through the pivotal attachments on their respective wheelframes, at variable elevations above their respective wheel frames, (c)two longitudinally spaced, transversely disposed, rigid, horizontal toolmount bars, each resiliently pivotally attached, adjacent its two ends,to the two said rock shafts, said tool mount bars being disposed abovesaid rock shafts and adapted to support two ranks of ground workingtools, and (d) at least two longitudinally disposed, rigid, frame bars,transversely spaced along said tool mount bars and resiliently fastenedthereto to maintain the latter in spaced parallel relationships.
 5. Aresilient planar framework as claimed in claim 4, and further includinga third longitudinally spaced, transversely disposed, rigid horizontaltool mount bar resiliently fastened to the said two frame bars andadapted to support a third rank of ground working tools.
 6. A resilientplanar framework as claimed in claim 5 and further comprising, a centersection and at least one wing section, each section supporting amultiplicity of ground working tools, each said wing sectioncomprising:(a) a horizontally and longitudinally disposed wing sectionwheel frame supported on at least two longitudinally spaced wheels, (b)a rigid, horizontally disposed wing section rock shaft, pivotallyattached to said wing section wheel frame at points proximate saidwheels and adapted to pivot relative to said wheel frame on a horizontallongitudinal axis passing through said points of pivotal attachment tosaid wheel frame, at variable elevations above said wheel frame, (c)longitudinally spaced, transversely disposed, rigid, horizontal, wingsection tool mount bars, each one being aligned with a correspondingtool mount bar of said center section, resiliently pivotally attached atits end nearer the center section to the adjacent end of thecorresponding tool mount bar of the adjacent section, and adapted topivot resiliently on a horizontal axis through the respective pivotalattachments between the corresponding tool mount bars, the distal endsof first and second of said tool mount bars of said wing section beingresiliently pivotally attached to and disposed above said wing sectionrock shaft, and (d) a longitudinally disposed, rigid, wing section framebar, resiliently fastened to each said wing section tool mount bar tomaintain the latter in spaced parallel relationship.
 7. A resilientplanar framework as claimed in claim 1 in which the rigid structuralmembers fastened by resilient fastenings are parallel, spaced, toolmount bars fastened resiliently to frame bars which maintain the toolmount bars in spaced parallel relationships, said tool mount bars beingfastened resiliently to a respective frame bar by a respective pair ofclevis and tongue mounted spherical bushings forming a pair of ball andsocket joints.
 8. A framework carrying the ground-working tools of afarm implement comprising at least one substantially planar horizontalsection of interconnected structural members wherein each sectioncomprises:(1) a plurality of interconnected rigid tool mount membershaving an orientation generally transverse to the direction of travelwhen working, and (2) a plurality of flexibly interconnecting linksbetween said tool mount members transmitting, between said tool mountmembers, torsional stress of said tool mount members around axesgenerally transverse to the direction of travel, wherein:(a) saidflexibly interconnecting links provide for flexibility substantiallyonly about axes generally parallel to the direction of travel of theimplement, and, (b) said interconnecting links provide for limited tozero flexibility about other axes, to relieve stress in the framework.9. A framework as claimed in claim 8 which further comprises at leastone additional rigid structural member interconnected between two ofsaid tool mount members by pivotal connections wherein at least one ofsaid pivotal connections permits relative movement around axes at rightangles to the pivotal axis.
 10. A framework as claimed in claim 9,wherein there is a plurality of said horizontal sections pivotallyattached in a line transverse to the direction of travel when workingthe pivotal attachments between adjacent sections being on axesgenerally parallel to said direction of travel and being adapted topermit relative movement between adjacent parts of said horizontalsections around axes at right angles to their pivotal axes.
 11. Aframework as claimed in claim 10 in which the interconnected structuralmembers are rigid.
 12. A framework as claimed in claim 9 in which theinterconnected structural members are rigid.
 13. A framework as claimedin claim 8, wherein there is a plurality of said horizontal sectionspivotally attached in a line transverse to the direction of travel whenworking, the pivotal attachments between adjacent sections being on axesgenerally parallel to said direction of travel and being adapted topermit relative movement between adjacent parts of said horizontalsections around aces at right angles to their pivotal axes.
 14. Aframework as claimed in claim 13 in which the interconnected structuralmembers are rigid.
 15. A framework as claimed in claim 8 in which theinterconnected structural members are rigid.